logger: add NewStdLogger and RedirectStdLogger

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

logger/logger_test.go

@@ -3,9 +3,37 @@ package logger
 import (
 	"bytes"
 	"context"
+	"log"
 	"testing"
 )
 
+func TestRedirectStdLogger(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(WithLevel(TraceLevel), WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	fn := RedirectStdLogger(l, ErrorLevel)
+	defer fn()
+	log.Print("test")
+	if !bytes.Contains(buf.Bytes(), []byte(`"level":"error","msg":"test","timestamp"`)) {
+		t.Fatalf("logger error, buf %s", buf.Bytes())
+	}
+}
+
+func TestStdLogger(t *testing.T) {
+	buf := bytes.NewBuffer(nil)
+	l := NewLogger(WithLevel(TraceLevel), WithOutput(buf))
+	if err := l.Init(); err != nil {
+		t.Fatal(err)
+	}
+	lg := NewStdLogger(l, ErrorLevel)
+	lg.Print("test")
+	if !bytes.Contains(buf.Bytes(), []byte(`"level":"error","msg":"test","timestamp"`)) {
+		t.Fatalf("logger error, buf %s", buf.Bytes())
+	}
+}
+
 func TestLogger(t *testing.T) {
 	ctx := context.TODO()
 	buf := bytes.NewBuffer(nil)

logger/stdlogger.go

@@ -1,6 +1,7 @@
 package logger
 
 import (
+	"bytes"
 	"log"
 )
 
@@ -14,6 +15,21 @@ func NewStdLogger(l Logger, level Level) *log.Logger {
 }
 
 func (sl *stdLogger) Write(p []byte) (int, error) {
+	p = bytes.TrimSpace(p)
 	sl.l.Log(sl.l.Options().Context, sl.level, string(p))
 	return len(p), nil
 }
+
+func RedirectStdLogger(l Logger, level Level) func() {
+	flags := log.Flags()
+	prefix := log.Prefix()
+	writer := log.Writer()
+	log.SetFlags(0)
+	log.SetPrefix("")
+	log.SetOutput(&stdLogger{l: l, level: level})
+	return func() {
+		log.SetFlags(flags)
+		log.SetPrefix(prefix)
+		log.SetOutput(writer)
+	}
+}